/**
 * @author spidersharma / http://eduperiment.com/
 */

import {
	AdditiveBlending,
	Color,
	DoubleSide,
	LinearFilter,
	Matrix4,
	MeshBasicMaterial,
	MeshDepthMaterial,
	NoBlending,
	RGBADepthPacking,
	RGBAFormat,
	ShaderMaterial,
	UniformsUtils,
	Vector2,
	Vector3,
	WebGLRenderTarget
} from "../three.module.js";
import { Pass } from "../postprocessing/Pass.js";
import { CopyShader } from "../shaders/CopyShader.js";

var OutlinePass = function (resolution, scene, camera, selectedObjects) {

	this.renderScene = scene;
	this.renderCamera = camera;
	this.selectedObjects = selectedObjects !== undefined ? selectedObjects : [];
	this.visibleEdgeColor = new Color(1, 1, 1);
	this.hiddenEdgeColor = new Color(0.1, 0.04, 0.02);
	this.edgeGlow = 0.0;
	this.usePatternTexture = false;
	this.edgeThickness = 1.0;
	this.edgeStrength = 3.0;
	this.downSampleRatio = 2;
	this.pulsePeriod = 0;

	Pass.call(this);

	this.resolution = (resolution !== undefined) ? new Vector2(resolution.x, resolution.y) : new Vector2(256, 256);

	var pars = { minFilter: LinearFilter, magFilter: LinearFilter, format: RGBAFormat };

	var resx = Math.round(this.resolution.x / this.downSampleRatio);
	var resy = Math.round(this.resolution.y / this.downSampleRatio);

	this.maskBufferMaterial = new MeshBasicMaterial({ color: 0xffffff });
	this.maskBufferMaterial.side = DoubleSide;
	this.renderTargetMaskBuffer = new WebGLRenderTarget(this.resolution.x, this.resolution.y, pars);
	this.renderTargetMaskBuffer.texture.name = "OutlinePass.mask";
	this.renderTargetMaskBuffer.texture.generateMipmaps = false;

	this.depthMaterial = new MeshDepthMaterial();
	this.depthMaterial.side = DoubleSide;
	this.depthMaterial.depthPacking = RGBADepthPacking;
	this.depthMaterial.blending = NoBlending;

	this.prepareMaskMaterial = this.getPrepareMaskMaterial();
	this.prepareMaskMaterial.side = DoubleSide;
	this.prepareMaskMaterial.fragmentShader = replaceDepthToViewZ(this.prepareMaskMaterial.fragmentShader, this.renderCamera);

	this.renderTargetDepthBuffer = new WebGLRenderTarget(this.resolution.x, this.resolution.y, pars);
	this.renderTargetDepthBuffer.texture.name = "OutlinePass.depth";
	this.renderTargetDepthBuffer.texture.generateMipmaps = false;

	this.renderTargetMaskDownSampleBuffer = new WebGLRenderTarget(resx, resy, pars);
	this.renderTargetMaskDownSampleBuffer.texture.name = "OutlinePass.depthDownSample";
	this.renderTargetMaskDownSampleBuffer.texture.generateMipmaps = false;

	this.renderTargetBlurBuffer1 = new WebGLRenderTarget(resx, resy, pars);
	this.renderTargetBlurBuffer1.texture.name = "OutlinePass.blur1";
	this.renderTargetBlurBuffer1.texture.generateMipmaps = false;
	this.renderTargetBlurBuffer2 = new WebGLRenderTarget(Math.round(resx / 2), Math.round(resy / 2), pars);
	this.renderTargetBlurBuffer2.texture.name = "OutlinePass.blur2";
	this.renderTargetBlurBuffer2.texture.generateMipmaps = false;

	this.edgeDetectionMaterial = this.getEdgeDetectionMaterial();
	this.renderTargetEdgeBuffer1 = new WebGLRenderTarget(resx, resy, pars);
	this.renderTargetEdgeBuffer1.texture.name = "OutlinePass.edge1";
	this.renderTargetEdgeBuffer1.texture.generateMipmaps = false;
	this.renderTargetEdgeBuffer2 = new WebGLRenderTarget(Math.round(resx / 2), Math.round(resy / 2), pars);
	this.renderTargetEdgeBuffer2.texture.name = "OutlinePass.edge2";
	this.renderTargetEdgeBuffer2.texture.generateMipmaps = false;

	var MAX_EDGE_THICKNESS = 4;
	var MAX_EDGE_GLOW = 4;

	this.separableBlurMaterial1 = this.getSeperableBlurMaterial(MAX_EDGE_THICKNESS);
	this.separableBlurMaterial1.uniforms["texSize"].value = new Vector2(resx, resy);
	this.separableBlurMaterial1.uniforms["kernelRadius"].value = 1;
	this.separableBlurMaterial2 = this.getSeperableBlurMaterial(MAX_EDGE_GLOW);
	this.separableBlurMaterial2.uniforms["texSize"].value = new Vector2(Math.round(resx / 2), Math.round(resy / 2));
	this.separableBlurMaterial2.uniforms["kernelRadius"].value = MAX_EDGE_GLOW;

	// Overlay material
	this.overlayMaterial = this.getOverlayMaterial();

	// copy material
	if (CopyShader === undefined)
		console.error("OutlinePass relies on CopyShader");

	var copyShader = CopyShader;

	this.copyUniforms = UniformsUtils.clone(copyShader.uniforms);
	this.copyUniforms["opacity"].value = 1.0;

	this.materialCopy = new ShaderMaterial({
		uniforms: this.copyUniforms,
		vertexShader: copyShader.vertexShader,
		fragmentShader: copyShader.fragmentShader,
		blending: NoBlending,
		depthTest: false,
		depthWrite: false,
		transparent: true
	});

	this.enabled = true;
	this.needsSwap = false;

	this.oldClearColor = new Color();
	this.oldClearAlpha = 1;

	this.fsQuad = new Pass.FullScreenQuad(null);

	this.tempPulseColor1 = new Color();
	this.tempPulseColor2 = new Color();
	this.textureMatrix = new Matrix4();

	function replaceDepthToViewZ(string, camera) {

		var type = camera.isPerspectiveCamera ? 'perspective' : 'orthographic';

		return string.replace(/DEPTH_TO_VIEW_Z/g, type + 'DepthToViewZ');

	}

};

OutlinePass.prototype = Object.assign(Object.create(Pass.prototype), {

	constructor: OutlinePass,

	dispose: function () {

		this.renderTargetMaskBuffer.dispose();
		this.renderTargetDepthBuffer.dispose();
		this.renderTargetMaskDownSampleBuffer.dispose();
		this.renderTargetBlurBuffer1.dispose();
		this.renderTargetBlurBuffer2.dispose();
		this.renderTargetEdgeBuffer1.dispose();
		this.renderTargetEdgeBuffer2.dispose();

	},

	setSize: function (width, height) {

		this.renderTargetMaskBuffer.setSize(width, height);

		var resx = Math.round(width / this.downSampleRatio);
		var resy = Math.round(height / this.downSampleRatio);
		this.renderTargetMaskDownSampleBuffer.setSize(resx, resy);
		this.renderTargetBlurBuffer1.setSize(resx, resy);
		this.renderTargetEdgeBuffer1.setSize(resx, resy);
		this.separableBlurMaterial1.uniforms["texSize"].value = new Vector2(resx, resy);

		resx = Math.round(resx / 2);
		resy = Math.round(resy / 2);

		this.renderTargetBlurBuffer2.setSize(resx, resy);
		this.renderTargetEdgeBuffer2.setSize(resx, resy);

		this.separableBlurMaterial2.uniforms["texSize"].value = new Vector2(resx, resy);

	},

	changeVisibilityOfSelectedObjects: function (bVisible) {

		function gatherSelectedMeshesCallBack(object) {

			if (object.isMesh) {

				if (bVisible) {

					object.visible = object.userData.oldVisible;
					delete object.userData.oldVisible;

				} else {

					object.userData.oldVisible = object.visible;
					object.visible = bVisible;

				}

			}

		}

		for (var i = 0; i < this.selectedObjects.length; i++) {

			var selectedObject = this.selectedObjects[i];
			selectedObject.traverse(gatherSelectedMeshesCallBack);

		}

	},

	changeVisibilityOfNonSelectedObjects: function (bVisible) {

		var selectedMeshes = [];

		function gatherSelectedMeshesCallBack(object) {

			if (object.isMesh) selectedMeshes.push(object);

		}

		for (var i = 0; i < this.selectedObjects.length; i++) {

			var selectedObject = this.selectedObjects[i];
			selectedObject.traverse(gatherSelectedMeshesCallBack);

		}

		function VisibilityChangeCallBack(object) {

			if (object.isMesh || object.isLine || object.isSprite) {

				var bFound = false;

				for (var i = 0; i < selectedMeshes.length; i++) {

					var selectedObjectId = selectedMeshes[i].id;

					if (selectedObjectId === object.id) {

						bFound = true;
						break;

					}

				}

				if (!bFound) {

					var visibility = object.visible;

					if (!bVisible || object.bVisible) object.visible = bVisible;

					object.bVisible = visibility;

				}

			}

		}

		this.renderScene.traverse(VisibilityChangeCallBack);

	},

	updateTextureMatrix: function () {

		this.textureMatrix.set(0.5, 0.0, 0.0, 0.5,
			0.0, 0.5, 0.0, 0.5,
			0.0, 0.0, 0.5, 0.5,
			0.0, 0.0, 0.0, 1.0);
		this.textureMatrix.multiply(this.renderCamera.projectionMatrix);
		this.textureMatrix.multiply(this.renderCamera.matrixWorldInverse);

	},

	render: function (renderer, writeBuffer, readBuffer, deltaTime, maskActive) {

		if (this.selectedObjects.length > 0) {

			this.oldClearColor.copy(renderer.getClearColor());
			this.oldClearAlpha = renderer.getClearAlpha();
			var oldAutoClear = renderer.autoClear;

			renderer.autoClear = false;

			if (maskActive) renderer.context.disable(renderer.context.STENCIL_TEST);

			renderer.setClearColor(0xffffff, 1);

			// Make selected objects invisible
			this.changeVisibilityOfSelectedObjects(false);

			var currentBackground = this.renderScene.background;
			this.renderScene.background = null;

			// 1. Draw Non Selected objects in the depth buffer
			this.renderScene.overrideMaterial = this.depthMaterial;
			renderer.setRenderTarget(this.renderTargetDepthBuffer);
			renderer.clear();
			renderer.render(this.renderScene, this.renderCamera);

			// Make selected objects visible
			this.changeVisibilityOfSelectedObjects(true);

			// Update Texture Matrix for Depth compare
			this.updateTextureMatrix();

			// Make non selected objects invisible, and draw only the selected objects, by comparing the depth buffer of non selected objects
			this.changeVisibilityOfNonSelectedObjects(false);
			this.renderScene.overrideMaterial = this.prepareMaskMaterial;
			this.prepareMaskMaterial.uniforms["cameraNearFar"].value = new Vector2(this.renderCamera.near, this.renderCamera.far);
			this.prepareMaskMaterial.uniforms["depthTexture"].value = this.renderTargetDepthBuffer.texture;
			this.prepareMaskMaterial.uniforms["textureMatrix"].value = this.textureMatrix;
			renderer.setRenderTarget(this.renderTargetMaskBuffer);
			renderer.clear();
			renderer.render(this.renderScene, this.renderCamera);
			this.renderScene.overrideMaterial = null;
			this.changeVisibilityOfNonSelectedObjects(true);

			this.renderScene.background = currentBackground;

			// 2. Downsample to Half resolution
			this.fsQuad.material = this.materialCopy;
			this.copyUniforms["tDiffuse"].value = this.renderTargetMaskBuffer.texture;
			renderer.setRenderTarget(this.renderTargetMaskDownSampleBuffer);
			renderer.clear();
			this.fsQuad.render(renderer);

			this.tempPulseColor1.copy(this.visibleEdgeColor);
			this.tempPulseColor2.copy(this.hiddenEdgeColor);

			if (this.pulsePeriod > 0) {

				var scalar = (1 + 0.25) / 2 + Math.cos(performance.now() * 0.01 / this.pulsePeriod) * (1.0 - 0.25) / 2;
				this.tempPulseColor1.multiplyScalar(scalar);
				this.tempPulseColor2.multiplyScalar(scalar);

			}

			// 3. Apply Edge Detection Pass
			this.fsQuad.material = this.edgeDetectionMaterial;
			this.edgeDetectionMaterial.uniforms["maskTexture"].value = this.renderTargetMaskDownSampleBuffer.texture;
			this.edgeDetectionMaterial.uniforms["texSize"].value = new Vector2(this.renderTargetMaskDownSampleBuffer.width, this.renderTargetMaskDownSampleBuffer.height);
			this.edgeDetectionMaterial.uniforms["visibleEdgeColor"].value = this.tempPulseColor1;
			this.edgeDetectionMaterial.uniforms["hiddenEdgeColor"].value = this.tempPulseColor2;
			renderer.setRenderTarget(this.renderTargetEdgeBuffer1);
			renderer.clear();
			this.fsQuad.render(renderer);

			// 4. Apply Blur on Half res
			this.fsQuad.material = this.separableBlurMaterial1;
			this.separableBlurMaterial1.uniforms["colorTexture"].value = this.renderTargetEdgeBuffer1.texture;
			this.separableBlurMaterial1.uniforms["direction"].value = OutlinePass.BlurDirectionX;
			this.separableBlurMaterial1.uniforms["kernelRadius"].value = this.edgeThickness;
			renderer.setRenderTarget(this.renderTargetBlurBuffer1);
			renderer.clear();
			this.fsQuad.render(renderer);
			this.separableBlurMaterial1.uniforms["colorTexture"].value = this.renderTargetBlurBuffer1.texture;
			this.separableBlurMaterial1.uniforms["direction"].value = OutlinePass.BlurDirectionY;
			renderer.setRenderTarget(this.renderTargetEdgeBuffer1);
			renderer.clear();
			this.fsQuad.render(renderer);

			// Apply Blur on quarter res
			this.fsQuad.material = this.separableBlurMaterial2;
			this.separableBlurMaterial2.uniforms["colorTexture"].value = this.renderTargetEdgeBuffer1.texture;
			this.separableBlurMaterial2.uniforms["direction"].value = OutlinePass.BlurDirectionX;
			renderer.setRenderTarget(this.renderTargetBlurBuffer2);
			renderer.clear();
			this.fsQuad.render(renderer);
			this.separableBlurMaterial2.uniforms["colorTexture"].value = this.renderTargetBlurBuffer2.texture;
			this.separableBlurMaterial2.uniforms["direction"].value = OutlinePass.BlurDirectionY;
			renderer.setRenderTarget(this.renderTargetEdgeBuffer2);
			renderer.clear();
			this.fsQuad.render(renderer);

			// Blend it additively over the input texture
			this.fsQuad.material = this.overlayMaterial;
			this.overlayMaterial.uniforms["maskTexture"].value = this.renderTargetMaskBuffer.texture;
			this.overlayMaterial.uniforms["edgeTexture1"].value = this.renderTargetEdgeBuffer1.texture;
			this.overlayMaterial.uniforms["edgeTexture2"].value = this.renderTargetEdgeBuffer2.texture;
			this.overlayMaterial.uniforms["patternTexture"].value = this.patternTexture;
			this.overlayMaterial.uniforms["edgeStrength"].value = this.edgeStrength;
			this.overlayMaterial.uniforms["edgeGlow"].value = this.edgeGlow;
			this.overlayMaterial.uniforms["usePatternTexture"].value = this.usePatternTexture;


			if (maskActive) renderer.context.enable(renderer.context.STENCIL_TEST);

			renderer.setRenderTarget(readBuffer);
			this.fsQuad.render(renderer);

			renderer.setClearColor(this.oldClearColor, this.oldClearAlpha);
			renderer.autoClear = oldAutoClear;

		}

		if (this.renderToScreen) {

			this.fsQuad.material = this.materialCopy;
			this.copyUniforms["tDiffuse"].value = readBuffer.texture;
			renderer.setRenderTarget(null);
			this.fsQuad.render(renderer);

		}

	},

	getPrepareMaskMaterial: function () {

		return new ShaderMaterial({

			uniforms: {
				"depthTexture": { value: null },
				"cameraNearFar": { value: new Vector2(0.5, 0.5) },
				"textureMatrix": { value: new Matrix4() }
			},

			vertexShader: [
				'varying vec4 projTexCoord;',
				'varying vec4 vPosition;',
				'uniform mat4 textureMatrix;',

				'void main() {',

				'	vPosition = modelViewMatrix * vec4( position, 1.0 );',
				'	vec4 worldPosition = modelMatrix * vec4( position, 1.0 );',
				'	projTexCoord = textureMatrix * worldPosition;',
				'	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );',

				'}'
			].join('\n'),

			fragmentShader: [
				'#include <packing>',
				'varying vec4 vPosition;',
				'varying vec4 projTexCoord;',
				'uniform sampler2D depthTexture;',
				'uniform vec2 cameraNearFar;',

				'void main() {',

				'	float depth = unpackRGBAToDepth(texture2DProj( depthTexture, projTexCoord ));',
				'	float viewZ = - DEPTH_TO_VIEW_Z( depth, cameraNearFar.x, cameraNearFar.y );',
				'	float depthTest = (-vPosition.z > viewZ) ? 1.0 : 0.0;',
				'	gl_FragColor = vec4(0.0, depthTest, 1.0, 1.0);',

				'}'
			].join('\n')

		});

	},

	getEdgeDetectionMaterial: function () {

		return new ShaderMaterial({

			uniforms: {
				"maskTexture": { value: null },
				"texSize": { value: new Vector2(0.5, 0.5) },
				"visibleEdgeColor": { value: new Vector3(1.0, 1.0, 1.0) },
				"hiddenEdgeColor": { value: new Vector3(1.0, 1.0, 1.0) },
			},

			vertexShader:
				"varying vec2 vUv;\n\
				void main() {\n\
					vUv = uv;\n\
					gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\
				}",

			fragmentShader:
				"varying vec2 vUv;\
				uniform sampler2D maskTexture;\
				uniform vec2 texSize;\
				uniform vec3 visibleEdgeColor;\
				uniform vec3 hiddenEdgeColor;\
				\
				void main() {\n\
					vec2 invSize = 1.0 / texSize;\
					vec4 uvOffset = vec4(1.0, 0.0, 0.0, 1.0) * vec4(invSize, invSize);\
					vec4 c1 = texture2D( maskTexture, vUv + uvOffset.xy);\
					vec4 c2 = texture2D( maskTexture, vUv - uvOffset.xy);\
					vec4 c3 = texture2D( maskTexture, vUv + uvOffset.yw);\
					vec4 c4 = texture2D( maskTexture, vUv - uvOffset.yw);\
					float diff1 = (c1.r - c2.r)*0.5;\
					float diff2 = (c3.r - c4.r)*0.5;\
					float d = length( vec2(diff1, diff2) );\
					float a1 = min(c1.g, c2.g);\
					float a2 = min(c3.g, c4.g);\
					float visibilityFactor = min(a1, a2);\
					vec3 edgeColor = 1.0 - visibilityFactor > 0.001 ? visibleEdgeColor : hiddenEdgeColor;\
					gl_FragColor = vec4(edgeColor, 1.0) * vec4(d,d,d,1.0);\
				}"
		});

	},

	getSeperableBlurMaterial: function (maxRadius) {

		return new ShaderMaterial({

			defines: {
				"MAX_RADIUS": maxRadius,
			},

			uniforms: {
				"colorTexture": { value: null },
				"texSize": { value: new Vector2(0.5, 0.5) },
				"direction": { value: new Vector2(0.5, 0.5) },
				"kernelRadius": { value: 1.0 }
			},

			vertexShader:
				"varying vec2 vUv;\n\
				void main() {\n\
					vUv = uv;\n\
					gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\
				}",

			fragmentShader:
				"#include <common>\
				varying vec2 vUv;\
				uniform sampler2D colorTexture;\
				uniform vec2 texSize;\
				uniform vec2 direction;\
				uniform float kernelRadius;\
				\
				float gaussianPdf(in float x, in float sigma) {\
					return 0.39894 * exp( -0.5 * x * x/( sigma * sigma))/sigma;\
				}\
				void main() {\
					vec2 invSize = 1.0 / texSize;\
					float weightSum = gaussianPdf(0.0, kernelRadius);\
					vec3 diffuseSum = texture2D( colorTexture, vUv).rgb * weightSum;\
					vec2 delta = direction * invSize * kernelRadius/float(MAX_RADIUS);\
					vec2 uvOffset = delta;\
					for( int i = 1; i <= MAX_RADIUS; i ++ ) {\
						float w = gaussianPdf(uvOffset.x, kernelRadius);\
						vec3 sample1 = texture2D( colorTexture, vUv + uvOffset).rgb;\
						vec3 sample2 = texture2D( colorTexture, vUv - uvOffset).rgb;\
						diffuseSum += ((sample1 + sample2) * w);\
						weightSum += (2.0 * w);\
						uvOffset += delta;\
					}\
					if( \
						vec3(diffuseSum/weightSum).r > 0.0 || \
						vec3(diffuseSum/weightSum).g > 0.0 || \
						vec3(diffuseSum/weightSum).b > 0.0  \
					){\
						float op = max( vec3(diffuseSum/weightSum).r, vec3(diffuseSum/weightSum).g ) ;\
						op = max(op, vec3(diffuseSum/weightSum).b );\
						gl_FragColor = vec4(diffuseSum, op);\
					}else {\
						gl_FragColor = vec4(diffuseSum/weightSum, 0.0);\
					}\
				}"
		});

	},

	getOverlayMaterial: function () {

		return new ShaderMaterial({

			uniforms: {
				"maskTexture": { value: null },
				"edgeTexture1": { value: null },
				"edgeTexture2": { value: null },
				"patternTexture": { value: null },
				"edgeStrength": { value: 1.0 },
				"edgeGlow": { value: 1.0 },
				"usePatternTexture": { value: 0.0 }
			},

			vertexShader:
				"varying vec2 vUv;\n\
				void main() {\n\
					vUv = uv;\n\
					gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\
				}",

			fragmentShader:
				"varying vec2 vUv;\
				uniform sampler2D maskTexture;\
				uniform sampler2D edgeTexture1;\
				uniform sampler2D edgeTexture2;\
				uniform sampler2D patternTexture;\
				uniform float edgeStrength;\
				uniform float edgeGlow;\
				uniform bool usePatternTexture;\
				\
				void main() {\
					vec4 edgeValue1 = texture2D(edgeTexture1, vUv);\
					vec4 edgeValue2 = texture2D(edgeTexture2, vUv);\
					vec4 maskColor = texture2D(maskTexture, vUv);\
					vec4 patternColor = texture2D(patternTexture, 6.0 * vUv);\
					float visibilityFactor = 1.0 - maskColor.g > 0.0 ? 1.0 : 0.5;\
					vec4 edgeValue = edgeValue1 + edgeValue2 * edgeGlow;\
					vec4 finalColor = edgeStrength * maskColor.r * edgeValue;\
					if(usePatternTexture)\
						finalColor += + visibilityFactor * (1.0 - maskColor.r) * (1.0 - patternColor.r);\
					gl_FragColor = finalColor;\
				}",
			blending: AdditiveBlending,
			depthTest: false,
			depthWrite: false,
			transparent: true
		});

	}

});

OutlinePass.BlurDirectionX = new Vector2(1.0, 0.0);
OutlinePass.BlurDirectionY = new Vector2(0.0, 1.0);

export { OutlinePass };
